Infra-red (IR) depth cameras project an invisible IR structured light pattern into the environment which is detected by an IR camera. Objects within the environment cause distortions in the structured light pattern as seen by the camera, which is off-axis compared to the light source and these distortions can be used to resolve depth information about the scene. These cameras, however, have a limited field of view and provide depth information from a single viewpoint so that an object which is close to the depth camera may occlude a large portion of the environment.
One solution which extends the area of the environment which can be mapped is to use more than one IR depth camera. This provides views of the scene from different perspectives and enables a 360° model of an object to be built up, but where the structured light patterns overlap, the accuracy of each IR depth camera is degraded.
The embodiments described below are not limited to implementations which solve any or all of the disadvantages of known IR depth camera systems.